1. Field of the Invention
The present invention relates to a light emitting diode, which particularly includes a permanent substrate plated beneath a mirror. The present invention also relates to a method for producing such high brightness light emitting diode.
2. Related Prior Arts
Currently, light emitting diodes (LEDs) are one of the most important light sources. The conventional procedures for producing LEDs are primarily to epitaxy a layered light emitting structure with pn junction on a GaAs substrate. The wafer is then bonded to a transparent substrate or a substrate with a mirror at high temperature. For bonding to the transparent substrate, processing temperature above 500° C. is necessary, and therefore the epitaxial structure is easily damaged. Certainly, the bonding yields and heat dissipation for the high power LED applications are not satisfied. As for bonding to the substrate with a mirror, the processing temperature is usually above 300° C., which also destroys the mirror and reduces reflectivity thereof.
R.O.C. Patent Application No. 477,079 disclosed a method for producing a semiconductor device having a permanent metal substrate formed by means of plating or sputtering. In this patent, at least one electrode is formed after the permanent metal substrate is completed. Therefore, damage and crack of the metal substrate and the epitaxial structure occur due to obvious difference between their coefficients of thermal expansion. Moreover, a metal substrate is temporarily deposited or plated on a semiconductor structure, and then removed after the permanent substrate is formed. In practice the epitaxial structure is also damaged during removal of the temporary metal substrate. In other words, it's difficult to form electrodes on opposite sides of an LED with a metal substrate.
Accordingly, it is desirable to provide an improved method for producing an LED with a plated substrate to mitigate and/or obviate the aforementioned problems.